In their debut business title, two venture capitalists offer an insightful, forward-thinking assessment of what makes

Silicon Valley tick.

If Silicon Valley can be held up as a living, breathing example of American ingenuity, why haven’t we been able to recreate it elsewhere? Hwang and Horowitt suggest that Silicon Valley is an innovation ecosystem they liken to a rainforest—hence, the book’s title. Thinking of Silicon Valley as a living biological system “helps innovators ‘tinker’ together in the same way that atoms ‘tinker’ together in natural biological systems ... [to] discover more valuable recipes for combining and recombining ideas, talent, and capital together.” The authors proceed to offer an engaging, highly creative analysis of the workings of a “rainforest,” using Silicon Valley as the prototype. They present 14 compelling “Rainforest Axioms,” for example, “Axiom #2: Rainforests are built from the bottom up, where irrational behavior reigns,” along with the “Rules of the Rainforest,” “Rule #4: Thou shalt experiment and iterate together.” The authors also explain how to build and measure a rainforest. The text is enhanced by well-designed graphic illustrations and explanatory charts. Hwang and Horowitt write with authority and wit, carefully backing up their theory with substantive examples. Readers get the feeling that the authors have unveiled a very big, important concept, one that could serve as the basis for intentionally, methodically developing other “rainforests” similar to Silicon Valley. However, they acknowledge that following the Valley’s winning formula is challenging, suggesting that “The Rainforest concept does not come naturally to many leaders” and that it requires “a new active capitalism” to create a rainforest. While Silicon Valley may not be entirely unique, replicating its ecosystem is no easy task.